Bending machine for rods with resettable folding shank

ABSTRACT

A digitally controlled machine for bending, forming, or curving raw parts, such as rods, wires or profiled sections, comprises a conventional main frame ( 1 ) and a rotating bending head capable of bending articles in different planes. The rod ( 4 ) is horizontally displaced along a transport axis ( 5 ) by a feed station, located upstream, and is brought through a bending shank ( 7 ) borne by the main frame ( 1 ). The rod is then brought through a lathe ( 10 ) of the bending head. The lathe is formed by a bending roll ( 8 ) and a folding pin ( 9 ), and is capable of rotating in a horizontal plane about an axis of rotation aligned with the axis of the bending roll ( 8 ). The bending shank ( 7 ) is movably mounted in translation in a transport axis ( 5 ) and is continuously displaced between one or more projecting bending positions wherein the shank is proximate to the roll ( 8 ) and one or more retracted positions, facing upstream, which completely clear the bending zone between the lathe and the main frame.

[0001] The present invention relates to an improvement to a numerically controlled machine for curving, forming, folding or bending bars or sections.

[0002] The invention also relates to the methods of controlling said machine.

[0003] Current machines of this type have limitations in various respects:

[0004] the loops are difficult to produce, particularly when their diameter is very large and they need to be closed.

[0005] the number of radii possible on one and the same part is often limited.

[0006] it is rarely possible to form loops at both ends of a part.

[0007] producing folds at the last end of a long part entails slowing the folding as a result of the high inertia of the part.

[0008] the flatness of closed frames is difficult to guarantee because of the twisting of the part on the initial wire.

[0009] a part having both large radii with a large wrap angle and small radii followed by short straight lengths pose problems of variation in folding pin/folding snout distance.

[0010] producing reverse folds (bayonets) takes time because of changes in sides of the folding pin.

[0011] soft or coated wires are difficult to work because of the constraints on contact and relative movement between tool and wire.

[0012] By designing a bending machine the folding and cutting snout of which is retractable, the applicant company has succeeded in achieving all the functions listed above, which functions were difficult or impossible to achieve beforehand.

[0013] This objective is achieved by the invention which consists in a numerically controlled machine for curving, forming, folding or bending a bar, the machine comprising in the conventional way a bed and a rotary bending head so as to be able to obtain folds in various planes, in which machine a bar is moved horizontally along a line of travel by a feed station arranged upstream, and conveyed through a folding snout carried by the bed then through a turner of the bending head, said turner being formed of a bending roller and of a folding pin, said turner being able to turn in a horizontal plane about an axis of rotation aligned with the axis of the bending roller, the machine being characterized in that the folding snout is mounted to move in translation along the line of travel and is moved continuously between one or more forward bending positions in which the snout is near the roller and one or more positions retracted toward the upstream end and totally freeing the bending region between the turner and the bed.

[0014] The invention will be better understood from reading the description which follows, given with reference to the following appended figures:

[0015]FIG. 1: outline drawing of the invention showing the various movements that can be accomplished on the machine.

[0016]FIGS. 2a, 2 b, 2 c: dynamics for producing a parallel-branch closed loop.

[0017]FIG. 3: outline drawing for producing loops or folds with different radii.

[0018]FIGS. 4a, 4 b, 4 c, 4 d, 4 e: dynamics for producing loops at both ends of a portion of wire.

[0019]FIG. 5: dynamics for producing the last fold in a long part.

[0020]FIG. 6: dynamics for producing flat closed parts.

[0021]FIGS. 7a, 7 b, 7 c, 7 d, 7 e: dynamics for producing a large arc with a large radius followed by a fold with a small radius.

[0022]FIGS. 8a, 8 b: dynamics for producing two opposing folds in one hit.

[0023]FIGS. 9a, 9 b, 9 c, 9 d: dynamics for folding without relative movement between the folding pin and the wire.

[0024] To simplify reading, the term “bar” has been used in the description and in the claims to denote more generally an unfinished part which may be a bar, a wire or a section prior to bending.

[0025] Also for simplification purposes, a choice has been made to describe the achievements and movements with respect to the horizontal plane of the figures, but these achievements can of course be reproduced in all the working planes.

[0026] A numerically controlled machine according to the invention (depicted schematically in a view from above in FIG. 1) comprises, in a conventional way, a bed (1) and a rotary bending head so as to be able to obtain folds in various planes.

[0027] A bar (4) is moved horizontally along a line of travel (5) by a feed station situated upstream (and not depicted) and is conveyed through a folding snout (7) carried by the bed (1) then through a turner (10) of the bending head, said turner being formed of a bending roller (8) and of a folding pin (9).

[0028] In a way known per se, the turner (10) can turn in a horizontal plane about an axis of rotation aligned with the axis of the bending roller (8).

[0029] According to one feature of the invention, the turner (10) is carried by a transverse carriage (2) able to move the turner in one direction and the other, at right angles to the direction of the line of travel.

[0030] According to one feature of the invention, a pickup gripper (3) is placed on the line of travel (5) downstream of the turner, for example on the outside thereof as in the figures. Said gripper is used only in certain operations which are detailed later on.

[0031] Thus, in the invention, the turner has two possibilities of moving:

[0032] a rotation in a horizontal plane so as to pivot the turner and produce either a fold angle between the bar portion (4 a) and the bar portion (4 b) passing through the turner by pressing against the snout (7), or a loop by forming on the bending roller (8).

[0033] a horizontal translation at right angles to the line of travel (5).

[0034] Furthermore, according to the main feature of the invention, the folding snout (7) and cutting means (6) are mounted so that they can move in terms of translation on the line of travel (5) and are continuously moved as one between one or more forward work positions in which the snout is near the roller (8) and one or more positions retracted toward the upstream end and totally freeing the working region between the turner and the bed.

[0035] In the examples shown, the cutting means (6) are placed upstream of the folding snout, on the line of travel, and move with it, but other locations are possible. It is the combination of these two new movements (translation of the turner+translation of the snout) with the already known movements (rotation of the turner and bar feed) which makes it possible for operations not previously achievable to be accomplished, for example:

[0036] Producing a closed loop:

[0037]  with the snout in the forward position, the start of the loop is produced by rotating the turner (10) to the left (FIG. 2a), then the loop itself is produced by rotating and translating the turner (10) to the right (FIG. 2b), and finally, once the snout has been withdrawn, the loop is closed at the desired angle, for example by returning the end of the bar to parallel to the line of travel (FIG. 2c).

[0038] Producing loops or folds with several radii: by changing the tool, it is possible to produce loops or folds with several radii (FIG. 3) using a stepped retractable shaft with several radii in combination with a snout of appropriate profile whose position with respect to the tool can be adjusted so as to guide the bar correctly and reduce the reaction against bending.

[0039]  “Producing the loop” is to be understood as meaning “producing a closed part” or producing bends of greater than 180°.

[0040] Producing loops at both ends of a length of bar:

[0041]FIG. 4a: rotating the turner (10) to the left begins the first loop, the snout being in a first forward position (7 a).

[0042]FIG. 4b: the snout is advanced in the downstream direction as far as a forward position (7 b) and rotating the turner (10) to the right closes the first loop.

[0043]FIG. 4c: once the straight length of bar has been fed through, the head pivots to the left to begin the second loop, the snout is still forward and placed in position (7 c) while the bending roller (8) is retracted under the snout.

[0044]FIG. 4d: the length of bar is picked up in the pickup gripper (3) so that the bar is cut to the desired length, and the head is moved in translation and turned to the right to bend the second loop then the snout is retreated to the cutting position (7 d).

[0045]FIG. 4e: the snout is retreated and retracted completely to position (7 e) to allow the turner (10) to continue its rotation to finish the second loop and free the end of the bar.

[0046] Producing the last fold in a long part: the pickup gripper (3) grasps the wire (9), the snout (7) and the cutting means (6) position themselves to cut the part to the desired length. Once the part has been cut, the snout disengages, retreating, and the turner (10) finishes the last fold in the long part (FIG. 5).

[0047] Producing flat closed parts (FIG. 6): the stages of work to finish the last fold that closes a frame are the same as for producing the last fold in a long part.

[0048] Producing a large arc with a large radius followed by a fold with a small radius:

[0049]FIG. 7a: the guide snout is replaced with an asymmetric snout (7 a′) with a folding shape of different radius (9 b).

[0050]FIG. 7b: the large arc of the part is begun by translation and rotation thereof to wind the part around the large radius of curvature (9 a), the snout being in position (7 b′).

[0051]FIG. 7c: the snout is advanced to (7′c), the head continues its translational and rotational movements to obtain the desired angle, for example to bring the end of the part back parallel to the line of travel (5) as in the figure.

[0052]FIG. 7d: the snout is retreated to position (7′d) to completely disengage the loop and place the snout in the chosen position for producing the fold, while the turner returns in translation to its starting position.

[0053]FIG. 7e: the snout advances to position (7′e), the turner continues its return in translation and produces the folding by rotating in the opposite direction to the previous one.

[0054] Producing two opposing folds in a single hit:

[0055]  the combination of the forward movements of the snout (7), the feed of the bar (4) and the translation of the turner makes it possible to produce two opposing folds simultaneously (FIGS. 8a, 8 b).

[0056] Folding without relative movement between the folding pin (9) and the bar:

[0057]  through the combination of movements (bar feed, forward movement of snout, folding, and raising of the head), the relative movement of the pin (9) with respect to the bar can be eliminated (FIGS. 9a to 9 d).

[0058] This list of embodiments is nonlimiting and the software controlling the machine can be developed to meet a specification.

[0059] The advantages of the invention are, nonlimitingly:

[0060] Production of large-diameter closed on unclosed loops.

[0061] Production of several radii on one and the same parts without limitation.

[0062] Formation of loops at both ends of one and the same part.

[0063] Production of a fold at the last end of a long part without slowing the folding.

[0064] Production of frames without the part twisting on itself, guaranteeing flatness of the frame.

[0065] Elimination of problems of variation in folding pin/folding snout distance.

[0066] Production of reverse folds without loss of time.

[0067] Work on soft or coated wires made possible by adjustment of contact between tool and wires.

[0068] Possibility of bringing the snout up close to the part during folding for good guidance and of retracting it at the last moment to free the working region.

[0069] Possibility of completing a loop by retracting the snout. 

1. A numerically controlled machine for curving, forming, folding or bending a bar, the machine comprising in the conventional way a bed (1) and a rotary bending head so as to be able to obtain folds in various planes, in which machine a bar (4) is moved horizontally along a line of travel (5) by a feed station arranged upstream, and conveyed through a folding snout (7) carried by the bed (1) then through a turner (10) of the bending head, said turner being formed of a bending roller (8) and of a folding pin (9), said turner (10) being able to turn in a horizontal plane about an axis of rotation aligned with the axis of the bending roller (8), characterized in that the folding snout (7) is mounted to move in translation along the line of travel (5) and is moved continuously between one or more forward bending positions in which the snout is near the roller (8) and one or more positions retracted toward the upstream end and totally freeing the bending region between the turner and the bed, and in that the turner (10) is carried by a transverse carriage (2) able to move said turner at right angles to the line of travel (5).
 2. The machine as claimed in claim 1, characterized in that cutting means (9) are placed upstream of the snout (7) on the line of travel (5) and move with said snout.
 3. The machine as claimed in one of claims 1 and 2, characterized in that a pickup gripper (3) is placed on the line of travel (5) downstream of the turner (10).
 4. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows the production of a closed loop: with the snout in the forward position, the start of the loop is produced by rotating the turner to the left, then the loop itself is produced by translating and rotating the turner to the right, and finally, once the snout has been withdrawn, the loop is closed at the desired angle.
 5. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows the production of loops or folds with several radii: using a stepped retractable shaft with several radii in combination with a snout of appropriate profile.
 6. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows the production of loops at both ends of a length of bar: rotating the turner (10) to the left begins the first loop, the snout being in a first forward position (7 a). the snout is advanced in the downstream direction as far as a forward position (7 b) and rotating the turner (10) to the right closes the first loop. once the straight length of bar has been fed through, the head pivots to the left to begin the second loop, the snout is still forward and placed in position (7 c) while the bending roller (8) is retracted under the snout. the length of bar is picked up in the pickup gripper (3), the snout is retreated to the bending position (7 d) and the turner is moved in translation and turned to the right to bend the second loop, then the snout is retreated to the cutting position. the snout is retreated and retracted completely to position (7 e) to allow the turner to continue its rotation and to finish the second loop.
 7. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows the production of the last fold in a long part: the pickup part (3) grasps the wire (9.), the snout (7) and the cutting means (6) position themselves; to cut the part to the desired length then the snout disengages, retreating, and the turner finishes the last fold in the long part.
 8. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows the production of flat closed parts: the stages of work to finish the last fold that closes a frame being the same as for producing the last fold in a long part.
 9. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows the production of a large arc with a large radius followed by a fold with a small radius: the guide snout is replaced with an asymmetric snout (7 a′) with a folding shape (9 b) of different radius. the large arc of the part is begun by translation and rotation thereof to wind the part around the large radius of curvature (9 a), the snout being in position (7 b′). the snout is advanced to (7′c), the head continues its translational and rotational movements to continue the loop and bring the end of the part back parallel to the line of travel (5). the snout is retreated to position (7′d) to completely disengage the loop and place the snout in the chosen position for producing the fold, while the head returns in translation to its starting position. the snout advances to position (7′e), the head continues its return in translation and produces the folding by rotating in the opposite direction to the previous one.
 10. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows the production of two opposing folds in a single hit, the combination of the forward movements of the snout (7) and the translation of the turner making it possible to produce two opposing folds simultaneously.
 11. A method of operation of a machine as claimed in one of claims 1 to 3, characterized in that it allows folding without relative movement between a folding pin (9) and the wire. 